Research on elephants shows value of habitat connectivity

06/15/2011

CORVALLIS, Ore. – A new study suggests that designing wildlife corridors for a charismatic wildlife species could benefit a range of other species – and aid more direct consideration of human-wildlife conflict in management.

The study, published in the journal Diversity and Distributions, explores the use of a focal species – in this case, the African elephant – to see if preserving movement routes for one group of large, wide-ranging animals would benefit other large mammals.

Lead author Clinton Epps, a wildlife ecologist from Oregon State University, spent 12 months over a two-year period hiking through a 20,000-square-kilometer region of Tanzania documenting what animal species used unprotected areas between reserves. Armed only with a can of bear spray and a machete, Epps, co-author Lauren Gwin and several young Tanzanian biologists looked at the distribution of elephants and other mammals inside and outside of wildlife reserves.

The team used cross-country walking transects, sightings and tracks to identify species in each location.

“The idea of focal species for conservation is not a new one,” said Epps, an assistant professor of fisheries and wildlife at OSU. “But whether that approach can be applied to connectivity between reserves is something that hasn’t been thoroughly examined on the ground. Are reserves like isolated islands, or will animals move back and forth between them and maintain genetic diversity?”

What Epps and his colleagues found was that elephants used specific routes and limited areas across the entire region, moving freely from reserves into unprotected areas without dense human settlement. And what was good for the elephants seemed to be good for many other species, Epps said. Although some species were found mainly within reserves – including lions, giraffes, zebras and buffalos – others such as kudu, leopards, hyenas and impalas ranged far outside.

Most importantly, even outside reserves Epps’ team found much higher diversity of large mammals where elephants occurred. Thus protecting elephant movement routes would help protect habitat connectivity for other species.

The wild card, Epps says, is human-wildlife conflict.

“When people encounter elephants outside reserves, it’s a big deal,” Epps pointed out. “The only people we heard about during the study who were killed by wildlife were killed by elephants. But people increasingly are moving into areas used by elephants as corridors, and in some cases, elephants have abandoned those routes. This potential conflict needs a solution that involves local communities, while recognizing the regional importance of these movement routes.”

Epps is working with co-author Benezeth Mutayoba of Sokoine University of Agriculture in Tanzania on just those kinds of issues. Wildlife resources are important to Tanzania, he said, accounting for 5 to 10 percent of the country’s gross national product – largely from tourism and hunting.

“It’s worth thinking about letting elephants maintain these connections between reserves,” Epps said. “Having a healthy elephant population is good for the economy and good for other animals. People there are concerned about elephant conflict and they are concerned about the safety of their families and their crops. But many also recognize the importance of wildlife.”

One possibility, Epps says, might be to identify “hot spots” where human activity and key elephant travel corridors intersect and focus on solutions in those areas.

“Ultimately, it is up to the people of Tanzania to decide what is best,” Epps said.

The study, which also included Justin Brashares from the University of California, as well as Gwin and Mutayoba, may also be applicable to connectivity planning in other environmental regions. Corridor designs for individual species frequently are proposed for the United States, Epps said, and this study provides an example of how to consider other species within such designs.